1. Field of the Invention
The present invention broadly relates to networked systems (such as via home area networks and the like) for controlling and distributing digital video recording and playback functions and information throughout t such networked systems. The present invention further relates to the efficient operation of such systems where the systems also include the distribution of the information among network-connected non-QoS devices such as PCs.
2. Background
Interactive digital TV recording and playback devices, which in essence are sophisticated set-top boxes with recording capabilities, are becoming more commonplace with advances in technology and the downward trend in prices. Along with a playback quality that is superior to analog-based systems, interactive digital TV recording and playback devices, e.g., Digital Video Recorders (DVRs), Personal Video Recorders (PVRs), Personal TV Receivers (PTRs), Personal Video Stations (PVSs), and Hard Disk Records (HDRs), also allow other features that are not practical with analog-based systems. Among such features is the ability of a user to engage in “live-pause” or “elastic” recording and playback.
Live-pause recording and playback allows a viewer/user with such an enabled system to watch a program live while the program is being simultaneously recorded, and also allows the user to use “trick play” modes or functions such as pausing the program or rewinding the program. While the recorded program is being paused or rewound, the system continues to record the program in a buffer memory. The system keeps track of where in memory the user has exited to perform trick play functions. The user can later return to the previous point of viewing in the program or skip with a “fast forward” operation up to the most current point of recording. Live-pause recording and playback allows the user the flexibility of watching a program live, already recorded, or a combination of both live and recorded viewing, along with other interesting trick play modes.
Existing interactive digital TV recording and playback devices, however, are designed to work with a single TV. Since an interactive digital TV recording and playback devices embody costly components such as a video encoder, e.g., MPEG 2 and a hard drive device (HDD), it is not generally cost effective to provide multiple interactive digital TV recording and play-back devices in a network system such as a Home Area Network (HAN).
Home Area Networks (HANs) are typically small-scale electronic cable, wire or wireless based communication networks used to interconnect a variety of small to moderate sized appliances, computers, and consumer electronic devices. Their cost and attributes make them especially suitable for typical homes or smaller buildings. Communication between devices may be via one or more of several well-known protocols or information formats. HANs can be general in their functionality, such as controlling the operation of several in-home devices such as appliances, television receivers, telephonic devices and burglar alarm systems, or they may be more specialized in their functionality, such as only controlling the operation of several television receivers and connecting the receivers to an external television program source such as a cable or satellite television service provider.
A well-designed and well-implemented HAN can allow resource sharing between one or more workhorse devices and other attached devices, providing such other attached devices with greater capability and functionality than they would otherwise possess.
Of special interest to the inventors of the subject matter of this Letters Patent are home area-networked interactive TV recording and playback systems having multiple television receivers/video display units or reproduction devices. It is desirable to be able to allow the playback of the same program on different receivers/video display units. Also desirable is the ability to allow live-pause playback and delayed viewing playback from more than one receiver. Further, it is desirable to allow a user to pause the playback of a program (whether in a live-pause or conventional playback mode) on one receiver, and to resume playback of the program from the pause point via one of the other receivers.
Quality of Service (QoS) devices (which are capable of self rate-limiting to comply with bandwidth allocations, and may be capable of negotiating with a system resource manager for varying amounts of bandwidth) such as newer digital television receivers and newer digital audio receivers are specially designed to better facilitate video and audio information traffic over HANs and similar types of networks, either between devices and a media server, or directly between two devices. However, a fully operational HAN often has non-QoS devices (which, by definition do not support QoS without additional hardware and/or software) connected thereto such as PCs and other “legacy” devices in order to make the functionality of the HAN more comprehensive.
Without the ability to integrate the QoS and non-QoS devices in the same HAN, individual networks would be needed to support QoS and non-QoS or legacy devices, respectively, leading to a redundant, costly and complex solution. It is also possible to retrofit the non-QoS devices with hardware and software interfaces to make them QoS-aware or capable, so that all network devices support advanced QoS protocols. This, however, is also a costly proposition.
The bandwidth requirements of the PCs and other non-QoS devices often require a great deal more bandwidth than is needed for video and/or audio stream transfers. Unless the video and audio receivers contain large buffer memory, which introduces a delay in reproduction of video and/or audio, the reproduction of video and/or audio streams in such systems is time sensitive, so that interruptions or delays in the transmission of video and/or audio information can lead to missed or lost information during reproduction or storage. As a result, when two non-QoS devices establish a high-bandwidth network connection, they often capture the network capacity for periods of time to the exclusion of, and at the expense of the QoS devices. Time-sensitive video and/or audio information may then be delayed or lost while the network is captured by the non-QoS devices.
What is of great interest but not provided in the prior art, is a HAN-based system that is flexible enough to efficiently distribute time-sensitive digital video and/or audio information to QoS devices, but also allow information transfers among non-QoS devices that require high bandwidth, without degradation in the normal performance of either the QoS or non-QoS devices.